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(Message started by: MartinReid on Apr 27th, 2018, 9:26am)

Title: Using Jape with the OPK file editor
Post by MartinReid on Apr 27th, 2018, 9:26am
For information; I'm posting this on the forum rather that a direct email to Jaap so others may be further tempted to practice with the excellent Jape.

For the attention of Jaap Scherphuis

Dear Jaap

I seem to remember you asking for 'trouble shooting bugs' with Jape; Well I thought I managed to crash it, but...

I created a pack in your OPK file editor, added some OPL's. Used the default Header Item Contents. Selected the pack and loaded it into Slot B of the emulator. Translated the OPLs and everything worked great.

So I started to get adventurous, In the OPK File Editor Header Item Contents I thought I would increase the pack size to 128k. Applied it, saved it, loaded it into Jape and it froze! The configuration dialogue was still active but the emulator was frozen. On closer inspection in the OPK file editor the time stamp for the 128k pack had changed... Year was blank and the month had jumped from 4 to 6 (see attached screen dump). For reference the current date/time stamp should be 27th April 2018.

I'm assuming it is this 'corrupt' header that is crashing Jape.

Anyway at least you know it is being used.

Sincerely and in good faith

PS. I found your 'Using the Comms Link' page great stuff. I've been looking for a PC with a native COM1 port to be able to use MAKE. Now I see I should be able to do it through DOSBox. I can't wait to try it on my tablet with Oliviers USB powered Comms Link encased in the Sourcerer's Top Slot Adaptor Cover.

Title: Re: Using Jape with the OPK file editor
Post by jaap on Apr 27th, 2018, 1:07pm
Thanks Martin for pointing out the header size/date bug in the OPK editor. It should be fixed now.

Note that it is possible to create invalid pack images with the opk editor. In particular, when you have a pack that is 128k or greater, it should have the "paged" flag set. Here is some in depth info about what that flag means:

- All physical 8k and 16K packs use the linear addressing mode. The "paged" flag will not be set when the pack is sized by the organiser. If the organiser wants to read from or write to a particular address on the pack, it has to start at address 0 and increment the address by 1 repeatedly until it reaches the correct address.

- Almost all physical 32k and 64K packs have hardware that uses paged addressing. The "paged" flag will be set when the pack is sized by the organiser. This mode allows the organiser to increase the pack address in steps of 256 to more quickly reach the address it wants to read from or write to. There are a few 32/64k packs that use linear addressing, making them compatible with the series 1 Organiser, but these are very rare. They are slower to read and write to.

- All physical 128k+ packs use a "segmented and paged" addressing mode. The "paged" flag will be set when the pack is sized by the organiser. There is no "segmented" flag, as it is simply assumed that packs of this size will use segmented addressing. The organiser can directly select which 16K segment to read from/write to, which is then addressed using paged addressing. This type is not supported by the CM model.

Unfortunately there is a bug in Jape where it cannot properly write to paged packs (they get corrupted). Linear packs work fine. So if you make a 32k/64k pack in the OPK file editor, you may decide to unset the paged flag to allow you to write to the pack in Jape. However, 128K packs (which are segmented) will probably confuse the organiser if they don't have the paged flag set, both in real life and in Jape.

Title: Re: Using Jape with the OPK file editor
Post by MartinReid on Apr 27th, 2018, 9:24pm
Dear Jaap

I see what you mean. I can crash Jape by trying to delete an OB3 from a paged 32k datapak.

Luckily I don't need to add or remove from my uploaded 128k pack, I just need to read from it. But thanks for the heads up about setting the Paged option; I'll also set the Write Protected option so it will return the Read Only Pack Error rather than crash.

While I'm waiting for my USB Comms Link to arrive from Olivier I'm trying to prepare my pack ready to practice using MAKE in DOSBox as outlined in your Using the Comms Link page.

Thanks again, sincerely

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